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There are operating systems that define `O_CREAT` with a different value than Linux, which uses `0x40`. For example, OpenBSD uses `0x0200`. Hence, we cannot use a hardcoded value. Also handle `O_TMPFILE` while here.
32 lines
976 B
XML
32 lines
976 B
XML
<!DOCTYPE qhelp PUBLIC
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"-//Semmle//qhelp//EN"
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"qhelp.dtd">
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<qhelp>
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<overview>
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<p>
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When opening a file with the <code>O_CREAT</code> or <code>O_TMPFILE</code> flag, the <code>mode</code> must
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be supplied. If the <code>mode</code> argument is omitted, some arbitrary bytes from the stack will be used
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as the file mode. This leaks some bits from the stack into the permissions of the file.
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</p>
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</overview>
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<recommendation>
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<p>
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The <code>mode</code> must be supplied when <code>O_CREAT</code> or <code>O_TMPFILE</code> is specified.
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</p>
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</recommendation>
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<example>
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<p>
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The first example opens a file with the <code>O_CREAT</code> flag without supplying the <code>mode</code>
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argument. In this case arbitrary bytes from the stack will be used as <code>mode</code> argument. The
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second example correctly supplies the <code>mode</code> argument and creates a file that is user readable
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and writable.
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</p>
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<sample src="OpenCallMissingModeArgument.c" />
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</example>
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</qhelp>
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